KR20220009711A - Polyimide solution - Google Patents

Abstract

The present application relates to a polyimide solution, a method for manufacturing the same, a polyimide comprising the same, and a semiconductor device comprising the same. The polyimide solution has excellent dielectric properties such as low dielectric constant and low dielectric loss tangent in a high-frequency band, has excellent solubility in an organic solvent, can prevent white cast and has excellent optical properties after curing.

Description

Polyimide solution {POLYIMIDE SOLUTION}

The present application relates to a polyimide solution, a method for manufacturing the same, a polyimide including the same, and a semiconductor device including the same.

Recently, the mobile communication industry market has entered the 5th generation mobile communication era. If network connectivity through smartphones was predominant in the existing 4G LTE market, 5G mobile communication services can provide large-capacity, low-latency, and fast transmission speed characteristics. Data utilization-based systems can be expanded to include Internet (IOT) devices, automobiles, robots, factories, and smart cities. Accordingly, the unprecedented data explosion and the semiconductor market for accommodating it are also expected to inevitably expand.

Accordingly, there is a need for a semiconductor device that stably implements 5G mobile communication performance. In particular, 5G mobile communication technology transmits and receives signals in a high frequency band compared to the existing 4G mobile communication technology, A characteristic for suppressing a decrease in transmission speed or loss of an electrical signal is required at a high level. That is, in order to obtain high reliability in a high-frequency band of gigahertz (GHz), the information processing capability of the semiconductor device should be improved without adversely affecting the transmission of electrical signals.

Accordingly, it is necessary to develop an adhesive material for forming an insulating layer having excellent processability due to excellent dielectric properties such as low dielectric constant and low dielectric loss tangent in a high frequency band, as well as excellent solubility in organic solvents.

The present application provides a polyimide solution having excellent dielectric properties such as low dielectric constant and low dielectric loss tangent in a high frequency band, excellent solubility in organic solvents, preventing cloudiness, and having excellent optical properties after curing.

This application relates to polyimide solutions. In one example, the polyimide solution may include a dianhydride monomer component and a diamine monomer component as polymerized units. In addition, the polyimide solution may include a polyimide resin and a solvent. In general, the polyamic acid exists in a solution state, and unlike a solid polyimide is formed after curing, the present application may be in the form of a solution in a polyimide state.

The polyimide solution of the present application may include two different solvents. In one example, the polyimide solution may include a first solvent having a vapor pressure of 1 to 8 hPa at 20° C. and a second solvent having a Hansen solubility index in the range ^{of 19 to 25 (J/cm 3} ) ^1/2. . In this application, by using the two solvents, the polyimide resin can be dissolved in a solution, so that it can be better dissolved in an organic solvent, and the process can be performed at a low curing temperature to improve optical properties, and also , the problem of cloudiness can be prevented.

In one example, the lower limit of the vapor pressure of the first solvent may be, for example, 1.1 hPa, 1.2 hPa, 1.3 hPa, 1.4 hPa, 1.5 hPa, 1.8 hPa, or 2 hPa or more at 20°C, and the upper limit is, for example, , 7 hPa, 5 hPa, 4 hPa, 3 hPa, 2.5 hPa, 1.9 hPa or 1.6 hPa or less. The lower limit of the Hansen solubility index of the second solvent is, for example, 19.2 (J/cm ³ ) ^1/2 , 19.4 (J/cm ³ ) ^1/2 , 19.5 (J/cm ³ ) ^1/2 , 19.8 ( J/cm ³ ) ^1/2 , 20(J/cm ³ ) ^1/2 , 20.3(J/cm ³ ) ^1/2 , 20.8(J/cm ³ ) ^1/2 , 21(J/cm ³ ) ^{1 /2} , 21.3 (J/cm ³ ) ^1/2 , 21.8 (J/cm ³ ) ^1/2 , 22 (J/cm ³ ) ^1/2 , or 22.1 (J/cm ³ ) ^{1/2 or} greater; , the upper limit is, for example, 24(J/cm ³ ) ^1/2 , 23.8(J/cm ³ ) ^1/2 , 23.5(J/cm ³ ) ^1/2 , 23.3(J/cm ³ ) ^1/2 , 23(J/cm ³ ) ^1/2 , 22.8(J/cm ³ ) ^1/2 , 22.5(J/cm ³ ) ^1/2 , 22.3(J/cm ³ ) ^1/2 , 22.2(J/cm ³ ) ^1/2 , or 22.15 (J/cm ³ ) ^1/2 or less. The first solvent may have a Hansen solubility index range of the second solvent, and the second solvent may also have a vapor pressure range of the first solvent. The two solvents may have the above physical properties at the same time, and in this case, may be referred to as a first solvent or a second solvent. In another example, at least the first solvent may be distinguished from the second solvent in that it does not have the Hansen solubility index range of the second solvent. In another example, the first solvent does not have the Hansen solubility index range of the second solvent, and the second solvent likewise does not have the vapor pressure range of the first solvent. The polyimide solution of the present application may include two or more different solvents, and may include solvents having the above two physical properties.

Since a solvent having a high vapor pressure is easily removed at a low curing temperature, optical properties can be improved during polyimide production. However, when a solvent is selected based only on the boiling point or vapor pressure, as the solvent volatilizes, the temperature decreases and absorbs ambient moisture, thereby reducing the overall solubility of the solution, resulting in cloudiness. A solvent having a certain level of polarity through the Hansen solubility index lowers moisture absorption, thereby preventing the cloudiness problem. In addition, when polymerizing a monomer having poor solubility in an organic solvent or including an additive such as a tertiary amine depending on the type of the monomer, the solubility of the polyimide solution itself decreases, so it is not necessary to increase the solubility of the entire solution. have. Accordingly, the present application provides a polyimide solution having excellent solubility in organic solvents, preventing cloudiness, and having excellent optical properties after curing by including two types of solvents having the above two physical properties.

In an embodiment of the present application, the second solvent may be included in 10 wt% or more of the total solvent. The lower limit of the range can be, for example, at least 15 wt%, 18 wt%, 23 wt%, 28 wt%, 30 wt%, 32 wt%, or 33 wt%, and the upper limit is, for example, 80 wt% , 70%, 60%, 50%, 45%, 43%, 40%, 38%, or 36% by weight. The first solvent may be included in 40% by weight or more of the total solvent, and in embodiments, the lower limit is 45% by weight, 50% by weight, 53% by weight, 55% by weight, 58% by weight, 60% by weight, 63% by weight, or 65% by weight or more, and the upper limit is, for example, 95% by weight, 93% by weight, 90% by weight, 88% by weight, 85% by weight, 83% by weight, 80% by weight, 78% by weight, 75% by weight, 73% by weight, 70% by weight, 68% by weight, or 65% by weight or less. In one example, the second solvent is 5 to 70 parts by weight, 8 to 68 parts by weight, 10 to 65 parts by weight, 11 to 60 parts by weight, 15 to 58 parts by weight, 20 to 55 parts by weight based on 100 parts by weight of the first solvent. parts, 25 to 54 parts by weight, or 43 to 54 parts by weight. When calculating the content range, if one solvent satisfies both the vapor pressure range of the first solvent and the Hansen solubility index range of the second solvent, the solvent is used in both the calculation of the first solvent content and the second solvent content can be calculated to be included in In the present application, within the above content range, desired properties of a polyimide solution and polyimide properties after curing may be implemented.

The solvent of the present application may be an organic solvent, and a solvent in which the polyamic acid or polyimide according to the present invention is sufficiently dissolved is used as the organic solvent. In one example, the first solvent or the second solvent may include at least one of an ester-based solvent and a ketone-based solvent. As the ester solvent, a cyclo or bicyclo ester solvent may be used. For example, gamma-butyrolactone, gamma-valerolactone, delta-valerolactone, gamma-caprolactone, ethyl acetate, butyl acetate, or Isobutyl acetate may be used, but is not limited thereto. In addition, as the ketone solvent, a cyclo or bicyclo ketone solvent may be used, and as an example, cyclopentanone, cyclohexanone, acetone, methyl ethyl ketone, diisobutyl ketone, and methyl isobutyl ketone may be used. have.

The first solvent of the present application may be a solvent added from the polymerization of the polyamic acid, and the second solvent may be a solvent added to the polyimide solution after imidization. In one embodiment, the first solvent may have a heterocyclic structure. The first solvent may be, for example, gamma-butyrolactone, gamma-valerolactone, delta-valerolactone or gamma-caprolactone. The second solvent may have an alicyclic structure. The second solvent may be, for example, cyclopentanone or cyclohexanone.

The polyimide solution according to the present application may include the dianhydride monomer represented by the following Chemical Formula 1 in a ratio of 40 mol% or more of the total dianhydride monomer component. The lower limit of the ratio may be, for example, 45 mol%, 48 mol%, 55 mol%, 60 mol%, 65 mol%, 68 mol%, 73 mol%, 78 mol%, 83 mol%, 88 mol%, or It may be 93 mol% or more, and the upper limit may be, for example, 100 mol%, 95 mol%, 90 mol%, 85 mol%, 80 mol%, 75 mol%, 73 mol%, or 65 mol% or less. In this application, by including 40 mol% or more of a dianhydride monomer having a specific structure of the following formula (1), in particular, a low dielectric loss tangent value is realized compared to the prior art, a polyimide solution is possible, and the desired physical properties such as excellent heat resistance after curing are realized. It is possible. Therefore, the polyimide according to the present application is used as a molded article such as a photosensitive layer and is suitable for use in a semiconductor device using a high frequency band for mobile communication.

Although the monomer of Formula 1 or the monomers described below is used to implement the above physical properties, the following monomer structure has relatively poor solubility in organic solvents (for example, a structure without fluorine in the molecular structure), and thus, The main content of the present application is to provide a polyimide solution and polyimide having desired physical properties by mixing with the solvent described above.

[Formula 1]

In Formula 1, R may be oxygen, a carbonyl group, an alkylcarbonyl group, a single bond, an alkylene group, or an alkylidene group. In addition, A ₁ and A ₂ may each independently be oxygen, a carbonyl group, an alkylcarbonyl group, a single bond, an alkylene group, or an alkylidene group. The A ₁ and A ₂ may be connected to any one carbon of an anhydride group present at both terminals. The alkylene group or alkylidene group may be unsubstituted or substituted with at least one substituent. The functional group may be, for example, an alkyl group, an alkenyl group, or an alkynyl group, but is not limited thereto. The alkyl group, alkenyl group, or alkynyl group may be linear, branched or cyclic, and may have 1 to 30 carbon atoms or 1 to 10 carbon atoms. The lower limit of the number of carbon atoms may be 1, 2, 3, or 4, and the upper limit may be 30, 25, 20, 15, 10 or 8 or less.

As used herein, the term "alkyl group", unless otherwise specified, has 1 to 30 carbon atoms, 1 to 25 carbon atoms, 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. may mean an alkyl group of The alkyl group may have a straight-chain, branched-chain or cyclic structure, and may be optionally substituted by one or more substituents. The substituent may be, for example, a polar functional group.

As used herein, the term "alkenyl group", unless otherwise specified, has 1 to 30 carbon atoms, 1 to 25 carbon atoms, 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to carbon atoms. It may mean an alkenyl group of 4. The alkenyl group may have a linear, branched or cyclic structure, and may be optionally substituted by one or more substituents. The substituent may be, for example, a polar functional group.

As used herein, the term "alkynyl group", unless otherwise specified, has 1 to 30 carbon atoms, 1 to 25 carbon atoms, 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to carbon atoms. It may mean an alkynyl group of 4. The alkynyl group may have a linear, branched or cyclic structure, and may be optionally substituted with one or more substituents. The substituent may be, for example, a polar functional group.

As used herein, the term "alkylene group", unless otherwise specified, has 2 to 30 carbon atoms, 2 to 25 carbon atoms, 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 10 carbon atoms, or carbon atoms. It may mean an alkylene group of 2 to 8. The alkylene group may have a linear, branched or cyclic structure, and may be optionally substituted by one or more substituents. The substituent may be, for example, a polar functional group.

In the present specification, the term "alkylidene group", unless otherwise specified, has 2 to 30 carbon atoms, 2 to 25 carbon atoms, 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 10 carbon atoms, or It may mean an alkylidene group having 2 to 8 carbon atoms. The alkylidene group may have a linear, branched or cyclic structure, and may be optionally substituted by one or more substituents. The substituent may be, for example, a polar functional group.

As used herein, the term “single bond” may refer to a bond connecting both atoms without any atoms. For example, when R is a single bond in Formula 1, both aromatic rings may be directly connected to each other.

In addition, the polyimide solution of the present application may include the diamine monomer of Formula 2 below in a ratio of 40 mol% or more of the total diamine monomer component. The lower limit of the ratio is, for example, 45 mol%, 48 mol%, 55 mol%, 60 mol%, 65 mol%, 68 mol%, 73 mol%, 78 mol%, 83 mol%, 88 mol%, 93 mol% It may be greater than or equal to mol% or 98 mol%, and the upper limit may be, for example, 100 mol%, 99 mol%, 98 mol%, or 97 mol% or less. The present application includes 40 mol% or more of a diamine monomer having a specific structure represented by the following formula (2), which in particular realizes a low dielectric constant value compared to the prior art, enables polyimide solution, improves solubility in organic solvents, and provides excellent heat resistance after curing It is possible to realize the desired physical properties.

[Formula 2]

In Formula 2, R is oxygen, a carbonyl group, an alkylcarbonyl group, a single bond, an alkylene group or an alkylidene group, A ₁ and A ₂ are each independently oxygen, a carbonyl group, an alkylcarbonyl group, a single bond, an alkylene group or an alkylidene group. The alkylene group or alkylidene group may be unsubstituted or substituted with at least one substituent. The substituent may be an alkyl group, an alkenyl group, or an alkynyl group, and in one example, the substituent may be an alkyl group substituted with at least one fluorine, and may be a perfluoroalkyl group in which all hydrogens are substituted with fluorine.

Formula 2 may be represented by, for example, Formula 4 below.

[Formula 4]

In Formula 4, Q is -C _a (CH ₃ ) _2a -, -C _b (CF ₃ ) _2b -, -(CH ₂ ) _c -, or -O(CH ₂ ) _d O-, a to d is each independently an integer of 1 to 4. The Q may be substituted with at least one fluorine. Further, in another example, the diamine monomer component may include two kinds of diamine monomers, and each monomer may be unsubstituted or substituted with highly polar fluorine. In addition, at least one of the two diamine monomers may include a compound represented by Formula 4, wherein R may be -C(CH ₃ ) ₂ - or -C(CF ₃ ) ₂ - . In one embodiment, any one of the two diamine monomers may be a compound derived from a dimer acid, which is a dimer of an unsaturated fatty acid such as oleic acid.

In addition, in an embodiment of the present application, the dianhydride monomer component may include at least one compound represented by the following formula (3).

[Formula 3]

Wherein M includes at least one or more from the group comprising an alkylene group, an alkylidene group, a carbonyl group, an alkylcarbonyl group, an alkoxy group, and a sulfonyl group, and M is at least one or more from the group comprising a fluorine and an alkyl group. substituted or unsubstituted. M in Formula 3 may be an alkylene group having as a substituent an alkyl group substituted with at least one fluorine. As an example, the alkyl group having 1 to 6 carbon atoms substituted with at least one fluorine may be a perfluoroalkyl group, specifically, a perfluoromethyl group. In another example, the dianhydride monomer component may include at least one dianhydride monomer substituted with at least one fluorine.

The dianhydride monomer of Formula 3 may be included, for example, in a ratio of 60 mol% or less of the total dianhydride monomer component. The lower limit of the ratio is, for example, 0 mol%, 5 mol%, 10 mol%, 15 mol%, 18 mol%, 23 mol%, 25 mol%, 30 mol%, 35 mol%, 40 mol%, or 55 mol% or more, and the upper limit may be, for example, 55 mol%, 53 mol%, 50 mol%, 45 mol%, 40 mol%, 35 mol%, or 33 mol% or less.

Since one of the main characteristics of polyimide resins in terms of molecular structure is rigidity, it has been generally used for devices requiring rigidity. In contrast, the polyimide resin according to the present invention contains a monomer component of a compound represented by at least one of Chemical Formulas 1 to 3 or at least one of Chemical Formulas 1 and 2, and thus has a flexible molecular structure compared to the prior art. Solubility may be improved, and polyimide based thereon may be suitable for implementation in a solution state.

In one example, the weight average molecular weight of the polyimide resin of the present invention may be 10,000 g/mol to 100,000 g/mol. The lower limit of the weight average molecular weight may be 15,000 g/mol, 20,000 g/mol, 25,000 g/mol, or 27,000 g/mol or more, and the upper limit of the weight average molecular weight is 90,000 g/mol, 80,000 g/mol, 70,000 g/mol , 60,000 g/mol, 50,000 g/mol, 30,000 g/mol, 29,000 g/mol, or 28,500 g/mol or less. Here, the weight average molecular weight means a value converted to standard polystyrene measured by gel permeation chromatograph (GPC). By adjusting the weight average molecular weight within the above range, the polyimide composition according to the present invention can be provided in the form of a solution, and a desired photosensitive polyimide composition can be formed with excellent processability.

In one example, the polyimide solution of the present invention may have a solid content of 20 to 70 wt% based on 100 parts by weight of the polyimide solution. The lower limit of the weight percent of solids may be 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, or 34 weight percent or more, and the upper limit of the weight percent of solids is 70, 65, 60, 55, 50, 45, 40, 37, 35, 34, or 33% by weight. By adjusting the solid content of the polyimide solution, it is possible to control the increase in viscosity and shorten the process time in the curing process.

In one example, the polyimide solution of the present invention may have a viscosity in the range of 1,000 to 50,000 cP measured ^{at a temperature of 23° C. and a shear rate of 1s −1 .} Specifically, the lower limit of the viscosity of the polyimide solution is 1,200 cP or more, 1,500 cP or more, 1,600 cP or more, 1,700 cP or more, 2,000 cP or more, 2,200 cP or more, 2,500 cP or more, 2,600 cP or more, 2,700 cP or more, 5,500 cP or more or more, 5,900 cP or more, 5,980 cP or more, 6,500 cP or more, 7,000 cP or more, 8,000 cP or more, 10,000 cP or more, 11,000 cP or more, 12,200 cP or more, 13,000 cP or more, 14,000 cP or more, 14,350 cP or more, 14,400 cP or more, 14,500 cP or more, 15,000 cP or more, or 15,500 cP or more, and the upper limit thereof is 49,000 cP or less, 45,000 cP or less, 40,000 cP or less, 30,000 cP or less, 25,000 cP or less, 20,000 cP or less, 18,000 cP or less, 16,000 cP or less, 15,500 cP or less, 15,000 cP or less, 14,500 cP or less, 8,000 cP or less, 5,000 cP or less, 3,500 cP or less, or 2,900 cP or less. In the present application, by controlling the viscosity range of the polyimide solution, it is possible to form a photosensitive polyimide composition having excellent processability and desired physical properties.

In one example, the polyimide of the present application may include a dianhydride component at at least one terminal, but is not limited thereto, and may include a diamine component at at least one terminal. In the present application, functional groups exemplified by -SH, -OH, Metacrylamide, or Olefin functional groups may be introduced by bonding the dianhydride component to the terminal, and accordingly, polyimides with various desired physical properties can be implemented.

In one example, at any point in the 3.4 to 10 GHz frequency band, the dielectric constant (Dk) after curing of the polyimide solution may be 3.5 or less. The lower limit of the dielectric constant after curing is not particularly limited, but may be, for example, 1.0 or more, and the upper limit may be 3.4, 3.3, 3.2, 3.1, 3.0, 2.95, or 2.9 or less. In addition, at any one point in the frequency band of 3.4 to 10 GHz, the dielectric loss tangent (Df) after curing of the polyimide solution may be 0.0035 or less. The lower limit of the dielectric loss tangent after curing is also not particularly limited, but may be, for example, 0.001 or more, and the upper limit may be 0.0034, 0.0033, 0.0032, 0.0031, 0.003, 0.0029 or less, and may be less than 0.0028 or less than 0.00275. Since the polyimide resin obtained by curing the polyimide solution of the present application has low values of both dielectric constant and dielectric loss tangent in a high frequency band, it may have excellent dielectric properties.

In particular, the frequency bands of 3.4 to 10 GHz, 4.0 to 10 GHz, 5.0 to 10 GHz, or 8.0 to 10 GHz are used in 5G mobile communication technology, which is a higher frequency band compared to the existing 4G mobile communication technology. That is, the polyimide of the present application can sufficiently exhibit a characteristic of suppressing a decrease in a transmission speed of an electrical signal or a loss of an electrical signal in a circuit in a semiconductor device when transmitting and receiving a signal in the specific high-frequency band. Accordingly, high reliability can be obtained by improving the information processing capability of the semiconductor device without adversely affecting the transmission of electrical signals.

In one example, the glass transition temperature after curing may be in the range of 100 ℃ to 300 ℃. In particular, the upper limit of the glass transition temperature after curing may be 295 ℃, 290 ℃, 285 ℃, 280 ℃, 275 ℃, 270 ℃, 265 ℃, 260 ℃, 255 ℃, 250 ℃, 245 ℃, 240 ℃ or 210 ℃ or less. and the lower limit thereof may be at least 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 195°C, 198°C, or 200°C. Since the polyimide resin according to the present invention has a relatively flexible molecular structure, the glass transition temperature after curing may have a particularly low value compared to other polyimide resins. Accordingly, the polyimide of the present invention is prepared in a solution state can be

Another embodiment of the present invention provides a method for preparing a polyimide. The manufacturing method may be the manufacturing method of the above-described polyimide solution.

First, the method for preparing a polyimide may include a step (step 1) of preparing a polyamic acid precursor solution by polymerizing a diamine monomer and a dianhydride monomer. The polyamic acid precursor solution may be prepared by one of the following methods, and the scope of the present invention is not limited thereto, and any known method may be used.

1) The whole amount of the diamine-based monomer is put in an organic solvent, and then the dianhydride-based monomer can be added so as to be substantially equimolar with the diamine monomer.

2) The whole amount of the dianhydride-based monomer may be put in an organic solvent, and then the diamine-based monomer may be added so as to be substantially equimolar with the dianhydride-based monomer.

3) After putting some components of the diamine-based monomer in the organic solvent, some components of the dianhydride-based monomer are mixed in a ratio of about 95 mol% to 105 mol% with respect to the reaction component, and then the remaining diamine-based monomer components are added and the remaining dianhydride-based monomer components may be continuously added thereto so that the diamine-based monomer and the dianhydride-based monomer are substantially equimolar.

4) After the dianhydride-based monomer is put in the organic solvent, some components of the diamine compound are mixed in a ratio of 95 mol% to 105 mol with respect to the reaction component, then another dianhydride-based monomer component is added and the remaining By adding the diamine-based monomer component, it may be added so that the diamine-based monomer and the dianhydride-based monomer are substantially equimolar.

5) A first polymer is formed by reacting a part of a diamine-based monomer component and a part of a dianhydride-based monomer component in an organic solvent in an excessive amount, and a part of a diamine-based monomer component and a part of a dianhydride in another organic solvent A method for forming a second polymer by reacting a monomer component in excess of any one, mixing the first and second polymers, and completing polymerization, wherein the diamine-based monomer component is formed when the first polymer is formed. In the case of excess, the dianhydride-based monomer component is excessive in the second polymer, and when the dianhydride-based monomer component is in excess in the first polymer, the diamine-based monomer component is in excess in the second polymer, The second polymers may be mixed and added so that the total diamine-based monomer component and the dianhydride-based monomer component used in these reactions are substantially equimolar.

Meanwhile, when preparing the polyamic acid precursor solution, the dianhydride monomer may be added in substantially equimolar amount with the diamine monomer, or may be added in an excess of the diamine monomer.

Next, it may include a step of stirring the polyamic acid precursor solution, through this, it is possible to obtain a polyamic acid solution (step 2).

In one example, separate heating may be performed in the stirring step, and heating may be performed within a temperature range of 20°C to 70°C. The temperature range is not particularly limited, but the lower limit of the heating temperature may be 22°C, 24°C, 25°C, 26°C, 28°C, 30°C, 32°C, 34°C, 36°C, or 38°C, and the upper limit thereof may be 65°C, 58°C, 56°C, 54°C, 52°C, 50°C, 48°C, 46°C, 44°C, or 42°C.

In one example, the heating step may be performed for 30 minutes to 5 hours. The heating time is not particularly limited, but the lower limit of the heating time may be 40 minutes, 45 minutes, 50 minutes, 55 minutes or 90 minutes, and the upper limit thereof is, for example, 4 hours, 3 hours, 150 minutes or 100 minutes. can In the present application, within the heating time range, unreacted substances can be minimized and storage stability of the polyamic acid solution can be secured.

Next, it may include a step of forming a polyimide solution (step 3). This is a step of imidizing polyamic acid to obtain a polyimide resin, and the imidization method may be a known method such as thermal imidization method of thermal dehydration and ring closure, chemical imidization method using a dehydrating agent, etc. Complex imidization may also be used.

In particular, it may be preferable to imidize under mild conditions such as chemical imidization that does not require high-temperature heat treatment, and in this case, pyridine, 2-methylpyridine, 3-methylpyridine, triethylamine, isoquinoline as a catalyst A tertiary amine such as these can be used as a catalyst, and acetic anhydride or the like can be used as a dehydrating agent. The tertiary amine may be included, for example, in the range of 0.8 to 2.0 equivalents relative to the number of moles of polyamic acid. In addition, the acetic anhydride may be included, for example, in the range of 2.5 to 4.0 equivalents relative to the number of moles of the polyamic acid.

Meanwhile, the polyimide resin obtained according to the present invention may be provided in the form of a solution, as described above.

The present application relates to a method for producing polyimide.

A polyimide can be formed by forming into a film by a well-known method using the obtained polyimide solution, drying and hardening. For example, the polyimide solution is cast on a support such as a glass substrate using a doctor blade or the like, and is usually 40° C. to 400° C. using a hot air dryer, an infrared dryer, a vacuum dryer, an inert oven, or the like. The polyimide can be formed by drying and curing in a temperature range of °C. The lower limit of the temperature may be 45 °C, 50 °C, 55 °C, or 60 °C, and the upper limit may be 350 °C, 300 °C, or 250 °C.

The present application provides a polyimide, which is a cured product of the above-described polyimide solution. The polyimide may be a photosensitive polyimide, and the above-described polyimide solution may be a photosensitive polyimide solution.

The photosensitive polyimide composition includes the above-mentioned polyimide, and since the polyimide according to the present invention has excellent solubility in a solvent, it can be provided as a solution. There is no need, therefore, a separate solvent may not be required, and it can be used as a molded article such as a photosensitive layer due to excellent processability.

The photosensitive polyimide composition may include a photoactive compound, and the photoactive compound may be used without limitation as long as it exhibits photosensitivity. In one example, the photoactive compound may be included in an amount of 1 to 50 parts by weight based on 100 parts by weight of the polyimide solution. If necessary, a sensitizer such as perylene, anthracene, thioxanthone, Michler ketone, benzophenone, or fluorene may be used in combination with the photoactive compound.

The strong light-sensitive polyimide resin composition may further include additives such as a dissolution rate control agent, a sensitizer, an adhesion enhancer, or a surfactant in addition to the above components.

The photosensitive polyimide composition of the present invention is applied on a substrate such as a glass substrate using a conventional method such as spin coating, slit spin coating, roll coating, die coating, and curtain coating, through the application process, exposure process, and development process steps. , can be used as a photosensitive layer. In the exposure process, the light source irradiated from the light irradiation means is not particularly limited, and examples of the light source include electromagnetic waves, visible light from ultraviolet rays, electron beams, X-rays, and laser light. The method of irradiating light by the light irradiation means is not particularly limited, and methods of irradiating with known light sources such as high-pressure mercury lamps, xenon lamps, carbon arc lamps, halogen lamps, cold cathode tubes for copiers, LEDs, and semiconductor lasers are exemplified. have. The developing process may be a process of exposing the photosensitive layer by the exposure process, curing the exposed region of the photosensitive layer, and then developing by removing the uncured region to form a pattern. The developer is not particularly limited, and examples thereof include an aqueous solution of an alkali metal or alkaline earth metal hydroxide or carbonate, hydrogen carbonate, aqueous ammonia, and a quaternary ammonium salt. The thickness of the photosensitive layer thus obtained may vary depending on the purpose, and may be, for example, 1 μm to 20 μm, but is not limited thereto.

The present application also provides a semiconductor device for 5G mobile communication. Here, 5G mobile communication may mean using a frequency band of 3.4 to 10 GHz. In the high frequency band, the photosensitive layer using the polyimide according to the present invention exhibits a low dielectric constant and a low dielectric loss tangent, and thus has excellent dielectric properties, and thus can greatly suppress the loss of electrical signals. can have high reliability.

In addition, the photosensitive layer made of the photosensitive polyimide composition according to the present invention is an interlayer insulating film, a passivation film, a buffer coating film, an insulating film for multilayer printed circuit boards, an OLED insulating film, as well as a thin film of a liquid crystal display device in a semiconductor device for 5th generation mobile communication. It can be used as a protective film of a transistor, an electrode protective film of an organic EL device, a semiconductor protective film, and the like.

The present application provides a polyimide solution having excellent dielectric properties such as low dielectric constant and low dielectric loss tangent in a high frequency band, excellent solubility in organic solvents, preventing cloudiness, and having excellent optical properties after curing.

1 and 2 are photographs showing results of Experimental Examples according to Examples and Comparative Examples of the present application.

Hereinafter, the present invention will be described in more detail through Examples according to the present invention and Comparative Examples not according to the present invention, but the scope of the present invention is not limited by the Examples presented below.

<Preparation of polyimide solution>

Example 1

Gamma-butyrolactone (GBL) was introduced while nitrogen was injected into a 500 ml reactor equipped with a stirrer and a nitrogen injection/discharge tube, and the temperature of the reactor was set to 40°C. First, 2,2-bis [4- (4-aminophenoxy phenyl)] hexafluoropropane (HFBAPP, 2,2-Bis [4- (4-aminophenoxy phenyl)] hexafluoropropane) monomer is added to proceed with dissolution and 4,4'-bisphenol A dianhydride (BPADA, 4,4'-Bisphenol A dianhydride) was added and stirred for at least 1 hour to react until there was no change in viscosity to obtain a polyamic acid solution.

To the polyamic acid solution, 1.0 equivalent of 3-methylpyridine (BP) relative to the number of moles of the polyamic acid, and 3.0 equivalents of acetic anhydride were added, and then heated to 70° C. and stirred for about 1 hour. , the imidization was carried out, and thereafter, it was cooled to room temperature. Distillation under reduced pressure was performed to remove impurities such as acetic acid. Cyclopentanone (CPN) was added to the imidized polyimide solution to prepare a polyimide solution. The cyclopentanone (CPN) is added so that the previously added gamma butyrolactone (GBL) and the cyclopentanone (CPN) have a weight ratio of 65:35.

Comparative Example 1

A polyimide solution was prepared in the same manner as in Example 1, except that cyclopentanone (CPN) was not added.

Experimental Example - Viscosity Measurement

Viscosity of the polyimide solutions prepared in Examples and Comparative Examples were measured using HAKKE Viscotester at ^{a shear rate of 1s −1} , a temperature of 23° C., and a plate gap of 1 mm.

Table 3 below shows the viscosity (cP @23°C) of the polyimide solution, the solid content (%), and the weight average molecular weight of the polyimide resin.

solid content
(%) Viscosity
(cP @23℃) weight average molecular weight
(g/mol) Example 1 31.9 2,770 26,500 Comparative Example 1 34.4 14,400 26,500

<Production of polyimide>

Example 1 and Comparative Example 1

The polyimide solution according to Example 1 and Comparative Example 1 was coated, and under a nitrogen atmosphere, the temperature was raised at 60° C. for 15 minutes, 110° C. for 10 minutes, and 300° C. for 1 hour to obtain polyimide in the form of a film.

Experimental Example - Thickness

The thickness of the polyimides prepared in Examples and Comparative Examples was measured using an Electric Film thickness tester manufactured by Anritsu Corporation.

Experimental example - dielectric constant and dielectric loss tangent measurement

The dielectric constant and dielectric loss tangent at 10 GHz of the polyimides prepared in Examples and Comparative Examples were measured at 23° C. and 50% RH using a Network Analyzer EVA Vector Network Analyzer (E5063A, Keysight Corporation).

Experimental Example - Measurement of Glass Transition Temperature

The glass transition temperatures of the polyimides prepared in Examples and Comparative Examples were measured at 10° C./min using DSC.

Experimental Example - Thermal decomposition temperature (Td) of 5 wt%

A thermogravimetric analysis Q50 model from TA was used, and the polyimide was heated to 150° C. at a rate of 10 min/° C. under a nitrogen atmosphere, and then water was removed by maintaining the isothermal temperature for 30 minutes. Thereafter, the temperature was increased to 600° C. at a rate of 10 min/° C., and the temperature at which a weight loss of 5% occurred was measured.

Table 2 below shows the results of thickness, dielectric constant, dielectric loss tangent and glass transition temperature measured according to the experimental examples of the polyimide.

thickness
(μm) permittivity
(@10GHz) dielectric loss tangent
(@10GHz) glass transition
Temperature (℃) pyrolysis temperature
(℃) Example 1 13 2.9 0.0027 198 527 Comparative Example 1 20 2.9 0.0028 200 530

Experimental Example - Cloudy phenomenon

After spin coating the polyimide solution according to Example 1 and Comparative Example 1, it was dried to check whether the polyimide solution was cloudy. Occurs when maintained for more than 5 minutes under a temperature of 25° C. and a relative humidity of 45 to 60% RH and confirmed with the naked eye. In Comparative Example 1, cloudiness occurred, whereas in Example 1, no cloudiness occurred. 1 and 2 show photographs of cloudiness of Example 1 and Comparative Example 1, respectively.

Claims (20)

A first solvent comprising a dianhydride monomer component and a diamine monomer component as polymerized units, a first solvent having a vapor pressure of 1 to 8 hPa at 20° C., and a Hansen solubility index in the range ^{of 19 to 25 (J/cm 3} ) ^1/2. 2 A polyimide solution containing a solvent. The polyimide solution according to claim 1, wherein the second solvent is included in an amount of 10 wt% or more based on the total solvent. The polyimide solution according to claim 1, wherein the second solvent is included in an amount of 5 to 70 parts by weight based on 100 parts by weight of the first solvent. The polyimide solution according to claim 1, wherein the first solvent or the second solvent comprises at least one of an ester solvent and a ketone solvent. The polyimide solution according to claim 1, wherein the first solvent has a heterocyclic structure. The polyimide solution according to claim 1, wherein the second solvent has an alicyclic structure. [Claim 2] The polyimide solution according to claim 1, wherein the dianhydride monomer of the following formula (1) is included in a proportion of 40 mol% or more of the total dianhydride monomer component:
[Formula 1]

In Formula 1, R is oxygen, a carbonyl group, an alkylcarbonyl group, a single bond, an alkylene group or an alkylidene group, A ₁ and A ₂ are each independently oxygen, a carbonyl group, an alkylcarbonyl group, a single bond, an alkylene group or an alkylidene group. [Claim 2] The polyimide solution according to claim 1, comprising the diamine monomer represented by the following formula (2) in a ratio of 40 mol% or more based on the total diamine monomer component:
[Formula 2]

In Formula 2, R is oxygen, a carbonyl group, an alkylcarbonyl group, a single bond, an alkylene group or an alkylidene group, A ₁ and A ₂ are each independently oxygen, a carbonyl group, an alkylcarbonyl group, a single bond, an alkylene group or an alkylidene group. The polyimide solution according to claim 1, wherein the dianhydride monomer component comprises at least one compound represented by the following formula (3):
[Formula 3]

Wherein M includes at least one or more from the group comprising an alkylene group, an alkylidene group, a carbonyl group, an alkylcarbonyl group, an alkoxy group, and a sulfonyl group, and M is at least one or more from the group comprising a fluorine and an alkyl group. substituted or unsubstituted. The polyimide solution according to claim 9, wherein M is an alkylene group having as a substituent an alkyl group substituted with at least one fluorine. The polyimide solution according to claim 1, wherein the weight average molecular weight is in the range of 10,000 g/mol to 100,000 g/mol. The polyimide solution according to claim 1, wherein the solids content is 20 to 70% by weight. The polyimide solution according to claim 1, wherein the viscosity measured at a temperature of 23° C. and ^{a shear rate of 1 s −1} is in the range of 1,000 to 50,000 cP. The polyimide solution according to claim 1, wherein at least one terminal includes a dianhydride. The polyimide solution according to claim 1, wherein the dielectric constant (Dk) after curing at any one point in the frequency band of 3.4 to 10 GHz is 3.5 or less. The polyimide solution according to claim 1, wherein the dielectric loss tangent (Df) after curing at any one point in the frequency band of 3.4 to 10 GHz is 0.0035 or less. The polyimide solution according to claim 1, wherein the glass transition temperature after curing is in the range of 100°C to 300°C. A method for producing a polyimide, wherein the polyimide solution according to claim 1 is cured at a temperature ranging from 40°C to 400°C. A photosensitive polyimide which is a cured product of the polyimide solution according to claim 1 . A semiconductor device for 5th generation mobile communication comprising the photosensitive polyimide according to claim 19.

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